<template>
  <!-- 通过评分来决定5个类名span 星是通过类名来实现的 -->
  <div class="star" :class="'star-'+size">
    <span class="star-item" v-for="(sc,i) in starCalss" :key="i" :class="sc"></span>
  </div>
</template>

<script>
// 类名常量
const CLASS_ON = "on"; //全星
const CLASS_HALF = "half"; //半星
const CLASS_OFF = "off"; //无星

export default {
  name: "Stars",
  props: {
    score: Number, //评分
    size: Number, //尺寸
  },
  computed: {
    /** 算法
     * 3.2: 3 + 0 + 2
     * 3.5 3 + 1 + 1
     */

    //只能塞on off 这2个都是n个 全星和无星   half(满足条件才添加0/1个) 半边星  这3个值是固定常量的 定义好点类名常量
    starCalss() {
      // 拿到评分
      const score = this.score;
      //定义数组 存放类名的
      const scs = [];
      // 向scs中添加n个CLASS_ON
      //思路是 取小数的正数出来循环添加on类名
      const scoreInteger = Math.floor(score);
      for (let i = 0; i < scoreInteger; i++) {
        scs.push(CLASS_ON);
      }
      // 向scs中添加0/1个CLASS_HALF
      //思路是 传递的评分 - 得到的正数 得到的小数  >= 0.5 就添加
      if (score * 10 - scoreInteger * 10 >= 5) {
        scs.push(CLASS_HALF);
      }
      // 向scs中添加n个CLASS_OFF  for  while都可以添加
      //思路是 数组长度 <5 因为是末尾了 所以判断长度 直接添加多少个就好
      while (scs.length < 5) {
        scs.push(CLASS_OFF);
      }
      //返回数组回去
      return scs;
    },
  },
};
</script>


<style lang="stylus" rel="stylesheet/stylus">
@import '../../common/stylus/mixins.styl';

.star { // 2x图 3x图
  float: left;
  font-size: 0;

  .star-item {
    display: inline-block;
    background-repeat: no-repeat;
  }

  &.star-48 {
    .star-item {
      width: 20px;
      height: 20px;
      margin-right: 22px;
      background-size: 20px 20px;

      &:last-child {
        margin-right: 0;
      }

      &.on {
        bg-image('./images/star48_on');
      }

      &.half {
        bg-image('./images/star48_half');
      }

      &.off {
        bg-image('./images/star48_off');
      }
    }
  }

  &.star-36 {
    .star-item {
      width: 15px;
      height: 15px;
      margin-right: 6px;
      background-size: 15px 15px;

      &:last-child {
        margin-right: 0;
      }

      &.on {
        bg-image('./images/star36_on');
      }

      &.half {
        bg-image('./images/star36_half');
      }

      &.off {
        bg-image('./images/star36_off');
      }
    }
  }

  &.star-24 {
    .star-item {
      width: 10px;
      height: 10px;
      margin-right: 3px;
      background-size: 10px 10px;

      &:last-child {
        margin-right: 0;
      }

      &.on {
        bg-image('./images/star24_on');
      }

      &.half {
        bg-image('./images/star24_half');
      }

      &.off {
        bg-image('./images/star24_off');
      }
    }
  }
}
</style>